CYCLIC SOFTENING OF EUROFER 97 AT ROOM TEMPERATURE-MECHANICAL AND MICROSTRUCTURAL BEHAVIOUR

M.F. GIORDANA; I. ALVAREZ-ARMAS; A.F. ARMAS

Jornada; III Jornadas de Ciencia y Tecnología; 2009

The quenched and tempered reduced-activation ferritic/martensitic steel EUROFER 97 subjected to cycling at room temperature has been studied. Under Low-Cycle Fatigue (LCF) test this steel shows, after the first few cycles, a pronounced cyclic softening accompanied by microstructural changes such as the decrease of the dislocation density inside the subgrain. During LCF tests, the softening seems to be governed by a mechanism independent of the plastic strain range imposed to the specimen. From the analysis of the peak tensile stress of the hysteresis loops and its respective correlation with the transmission electron microscopy observations can be concluded that the cyclic softening observed at room temperature could be attributed to the progressive annihilation of dislocations located in the interior of the subgrains.